Arrangement for emitting mixed light

Abstract

An arrangement for emitting mixed light including a primary and secondary radiation with at least one first electroluminescent light-source for emitting first primary radiation, at least one second electroluminescent light-source for emitting second primary radiation, and a light-converting element for absorbing at least one of the primary radiations and re-emitting the secondary radiation. The light-converting element is arranged so that the entire proportion of primary radiation in the mixed light passes through the light-converting element. The light-converting element is a ceramic light-converting material whose microstructure is selected to be such that the color point of the mixed light of primary and second radiation is substantially independent of the angle of viewing.

1. A light-converting element for mixing light, comprising:
 a first light source emitting a first primary radiation and a second light source emitting a second primary radiation; 
 a ceramic light converting element positioned over said first light source and said second light source and converting at least one of said primary radiations as an emitted secondary radiation; 
 an optical coupling layer positioned between said ceramic light converting element and said first light source and said second light source; 
 said ceramic light converting element having a microstructure selected to be such that the color point of the mixed light produced from said primary and said secondary radiation is substantially independent of an angle of viewing; 
 said ceramic light-converting material having a plurality of oxidic particles having a mean diameter of between about 50 nm to about 3000 nm, said ceramic light-converting material further having a plurality of pores having a mean diameter of between about 250 nm to about 2000 nm. 
 
     
     
       2. The light converting element of  claim 1  wherein said ceramic light converting element has a side wall, said side wall including a reflective layer. 
     
     
       3. The light converting element of  claim 1  wherein said first light source is positioned at about a right angle relative to said second light source. 
     
     
       4. The light converting element of  claim 1  wherein the first wavelength is in the blue or ultraviolet region of the spectrum and the second wavelength is in the red region of the spectrum. 
     
     
       5. The light converting element of  claim 1  wherein the difference between the refractive index of said ceramic light-converting material and the refractive index of said oxidic particles is more than 0.2. 
     
     
       6. The light converting element of  claim 1  wherein the density of the ceramic light-converting material is more than 97% of the theoretical maximum density of a corresponding crystalline material. 
     
     
       7. A light-converting element for mixing light, comprising:
 a first light source emitting a first primary radiation and a second light source emitting a second primary radiation; 
 a ceramic light converting element positioned over said first light source and said second light source and converting at least one of said primary radiations as an emitted secondary radiation; 
 said ceramic light converting element having a microstructure selected to be such that the color point of the mixed light produced from said primary and said secondary radiation is substantially independent of an angle of viewing; 
 said ceramic light-converting material having a plurality of oxidic particles, said ceramic light-converting material further having a plurality of pores; 
 wherein said first light source includes a plurality of light emitters substantially surrounding said second light source, said light converting element having a side wall substantially surrounded by a reflective layer. 
 
     
     
       8. The light converting element of  claim 7  wherein said reflective layer is an aluminum layer with a thickness of more than 30 nm. 
     
     
       9. The light converting element of  claim 7  wherein said oxidic particles have a mean diameter of between about 200 nm to about 1000 nm, said plurality of pores have a mean diameter of between about 700 nm to about 1200 nm. 
     
     
       10. A light-converting element for mixing light, comprising:
 a first light source emitting a first primary radiation and a second light source emitting a second primary radiation; 
 a ceramic light converting element positioned over said first light source and said second light source and converting at least one of said primary radiations as an emitted secondary radiation; 
 an optical coupling layer positioned between said ceramic light converting element and said first light source and said second light source; 
 said ceramic light-converting material having a plurality of oxidic particles having a mean diameter of between about 50 nm to about 3000 nm, said ceramic light-converting material further having a plurality of pores having a mean diameter of between about 250 nm to about 2000 nm; 
 wherein said ceramic light converting element has a side wall, said side wall including a reflective layer substantially surrounding said light converting element.